Known benefits of aerobic exercise include cardiovascular fitness, reduced susceptibility to illness, and weight control, in addition to simple recreation for many people. Weight bearing exercises, those in which the body must support itself, also have been shown to increase bone density. The lower body, i.e., the lower trunk and legs, contain the largest muscles in the body, and therefore are those most commonly utilized in aerobic workouts, with or without simultaneous exercise of other muscle groups.
There are many ways to achieve aerobic workouts of muscles of the lower body, one popular manner being "step aerobics" which uses a short, usually portable step. The user repeatedly steps onto and off of the step, sometimes in complicated sequences and open in conjunction with rhythmic music. Complicated patterns of exercise using such a step require considerable practice and balance, particularly as the level of exhaustion increases during a workout.
There are other fields of exercise, notably dance, such as ballet, that require regular practice and balance. In ballet, for example, it is common to use a long horizontal bar permanently attached to a wall for balance, although the ultimate objective is to perform without a balance aid.